Falling for the cowgirl / Jody Hedlund.

Enhanced descriptions from Syndetics:

Years ago, he shattered her heart. Now she must trust him with her life. As the only girl in her family, and with four older brothers, Ivy McQuaid can rope and ride with the roughest of ranchers. She's ready to have what she's always longed for--a home of her own. She's set her heart on a parcel of land south of Fairplay and is saving for it with her winnings from the cowhand competitions she sneaks into--but her dream is put in jeopardy when the man she once loved reappears in her life.After two years away, Jericho Bliss is back in South Park as an undercover Pinkerton agent searching for a war criminal. He has no intention of involving a woman in the dangerous life he leads, but one look at Ivy is all it takes for him to question the path he's set out for himself.Even though Jericho tries to resist his longtime attraction to the beautiful and vivacious Ivy, he finds himself falling hard and fast for her. In the process, his worst fear comes true--he puts her smack-dab in the middle of danger. With Ivy's life in the balance, will Jericho give her up once again, or will he find a way back to her, this time forever?